Floor mat and small animal rearing cage

ABSTRACT

A floor mat and a small animal rearing cage capable of healthfully rearing a small animal and eliminating the need of adding a specific breeding floor mat even when the small animal is bred, wherein the floor mat is laid on the floor of a rearing box forming the small animal rearing cage. The floor mat formed in a sheet having heat retaining property and flexibility has such a size that can enclose at least the body part of the small animal and laid on the floor of the rearing box so that walls of such a size that can hide at least the half of the body of the small animal can be formed. By utilizing walls formed with the meandering and overlapped sheet-like floor mat, the small animal assures a sleeping floor, an excretion place, and birth and breeding place where light and wind can be avoided. The sheet-like floor mat desirably has both water absorbency and deodorization property to suppress the occurrence of odor.

FIELD OF THE INVENTION

The present invention relates to a floor mat which is used for rearingsmall animals such as a mouse and a rat, and to a small animal rearingcage for rearing such small animals.

RELATED ART

Small animals including a squirrel, a hamster, a rat, a mouse, and arabbit are conventionally housed and reared in a small animal rearingcage as a pet or for a laboratory use. The cage is provided with a foodfeeder and water feeder, and the animals eat and evacuate in the cage.The cage is also provided with a floor formed with a plastic or metallicplate or a net, and a floor mat is laid thereon. The floor mat functionseither as an excretion disposal material to absorb and retain theexcrement of small animals and as their bedding material.

Materials such as wood chips, paper chips, ground corn cobs, recyclednon-woven fabrics have conventionally been sold and used as a floor mat.Among these, sawdust or wood, or paper chips are the most used materialas a floor mat. Sawdust or chips absorb excrement of small animals,however, have no deodorization property that removes offensive odorsubstances such as ammonia. In order to avoid generation of offensiveodor, the floor mat is required to be changed to new one frequently. Theproblem is that less frequent changing of the mat leads to generateoffensive odor. Sawdust or chips, as being an aggregation of smallpieces having a size of 1 to 2 cm or less in every direction, tend togenerate dust.

In order to solve aforementioned problems, a floor mat comprising acellulose material having a metal supported thereto has been proposed tocontrol the generation of offensive odor. (Japanese Patent ApplicationLaid-Open No. 2002-209465) The floor mat is composed of metal supportedcellulose that is obtained by having a metal that binds to offensiveodor substances such as hydrogen sulfide or ammonia supported to thecellulose fiber. The offensive odor substance, such as ammoniaoriginally generating from excrement of small animals, binds to a metalthat is supported by cellulose, and the generation of offensive odor isrestrained in low level.

The floor mat mentioned above is formed with a cotton-like substance orsmall pieces having a size of several centimeters in every direction,and are laid in large numbers in a small animal rearing cage. As aresult, a large number of cotton-like substances laid in the cage givelarger surface area as a whole and thus efficient absorption of urinecan be obtained. In the case where a floor mat with a certain thicknessis laid in the cage, small animals can use the mat as a material fortheir bedding or nesting. Small animals can thus be bred without havingnests provided in the cage.

When the small animals move around the cage, however, the floor matformed with many small substances having a size of only severalcentimeters in every direction are spread anywhere around the cage. Thisalso spreads excrement to clean area of the mat and thus leads todeterioration of rearing environment. In order to breed small animals byusing a floor mat as their nesting materials in the cage, the mat isrequired to be added or other mats to be provided. Particularly when asmall animal rearing cage is installed at a place where air-conditioningis conducted, sufficient amount of floor mat is required to be laid inorder to provide protection against the wind from the air-conditioningmachine that tends to cause the body temperature drop of baby animals.Further, according to a guideline on animal experiments developed byILAR (Institute of Animal Resources), the floor mat is recommended to bechanged every day or once a week, however, the floor mat shown abovecannot be reused and thus causes higher costs for purchasing anddisposal of the mat and yields unfavorable environmental effects.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of the present invention is toprovide a floor mat or a small animal rearing cage in which smallanimals are reared under hygienic condition and the necessity toreplenish the floor mat upon breeding is eliminated.

In order to overcome the foregoing problems, the present invention foundthat, not an aggregation of a plurality of small objects but a sheettype soft floor mat having a size of at least no less than 10 cm in sidelength is appropriate for the small animal rearing, particularly forreproduction, and completed the invention as such. The present inventionalso found that it is preferable that such sheet type soft floor mat isprovided with a function to deodorize excrement and urine, and furtherfound that the manner to lay the sheet has great effects on the rearingenvironment of small animals and completed the invention as such.

Specifically, the present invention provides:

(1) A floor mat laid in a small animals rearing cage for housing andrearing small animals, the floor mat is a sheet comprising a temperatureholding property to a degree that can keep the body temperature of thesmall animals, a flexibility to a degree that can wrap the body of thesmall animals, and a size that covers at least the entire abdomen of thesmall animals.

According to the invention described in (1), the sheet type floor matlaid in the small animals rearing cage has a sufficient size to coverthe entire body of the target small animals when the animals couch onthe mat, and thus the frequent movement of the animals does not causethe mat to be moved along the movement of the animals. For this reason,the mat avoids the excrement to be spread around the whole floor andtherefore avoid the deterioration of the rearing environment.

The aforementioned floor mat is provided with a sufficient temperatureholding property and flexibility so that the small animals can wrapthemselves therein to keep their body temperature. This makes thebleeding of the small animals easier because the parents or children canmake themselves wrapped in the mat even without having any nest box or afloor mat for bleeding in order to keep their body temperature at anecessary level and to avoid the wind blowing out from the airconditioning machine. The animals when wrapped in the mat can alsoobtain a dark hiding place and a peace of mind to release the stress andthus able to achieve higher reproductive performance.

Additionally, the sheet type floor mat shown above generates extremelyfewer dusts than the floor mats constituted by sawdust or chips andhardly adhered to the body surface of the baby animals that are justborn and have no hair. This prevents parents from eating their babyanimals who are adhered with the pieces of floor mat which arerecognized as a foreign object. The sheet type floor mat has a degree offlexibility such that it can be bent flexibly to wrap the small animalstherein and is freely bent to form folds in the rearing cage. The foldstrap the excrement of the animals and prevent the excrement to be spreadover the whole floor mat in the cage even when the animals move around.

As for the aforementioned mat, it is preferable to use a fabric having asize of at least one cm in side length in every direction. Paper orsurface treated vinyl sheeting to provide a temperature holding propertycan also be used.

(2) The floor mat according to (1), comprising a size for covering atleast the abdomen and the head of the small animals.

The floor mat should have a size to cover the abdomen of the smallanimals, however, it is preferable to have larger size with capacity towrap in not only their abdomen but also up to their head so that theycan hide almost all part of their body when they couch upon the mat. Themat prevents animals from being exposed to light and wind except theirtails and thus provides them with a comfortable living environment.

(3) The floor mat according to (1) or (2), further comprising a waterabsorption property and deodorization property.

According to the invention described in (3), the floor mat is providedwith water absorption and deodorization property in addition to thetemperature holding property and flexibility, so that the mat can absorbwater content of excrement of the small animals and can also remove theoffensive odor generated by the excrement. This keeps the small animalrearing cage in a hygienic environment without generating offensive odorfor a long period of time and thus the mat can be changed lessfrequently.

The “deodorization property” in this specification means to be providedwith one or both of the odor elimination property or/and odor removalproperty. Wherein “odor elimination property” means to chemicallyeliminate the offensive odor substance by having the target substancereacted with other substances or by decomposing the target substanceinto other substances; whereas “odor removal property” means tophysically remove the odor substance by way of absorption or exhaustion.

(4) The floor mat according to (1) or (3), further comprising a tearingresistance.

According to the invention described in (4), the floor mat comprisesstrength to a degree that cannot be torn by being pulled by hands. Themat thus ensures longer use as it may not be damaged by the smallanimals moving around the cage or biting the mat several times. As themat is hard to be torn off, the excrement adhered to the mat can beeasily brushed off. The mat can also be washed for further use andthereby reducing the total amount of waste disposal.

The “tearing resistance” in this specification means a property that ishard to be torn by small animals moving around the cage or having a fewbiting of the mat. Owing to this property, the mat is hardly torn intosmall pieces, lumps or dusts even when the small animals bite or pull onthe floor mat 60.

(5) The floor mat according to (4), comprising an improved cellulosefabric wherein carboxyl group-introduced cellulose is formed in a shapeof sheet.

Specific examples of the floor mat that is provided with temperatureretaining property, flexibility, water absorption property,deodorization property and tearing resistance property include a fabricsupported by the known deodorization substance. Among these, theimproved cellulose fabric described in (5) is particularly preferablebecause it is provided with temperature retaining property, flexibility,water absorption property, and deodorization property, and is hardlybitten to be torn by small animals particularly by mouse and can bewashed by washing machines. Since the improved cellulose fabric obtainsthe deodorization property by way of an introduction of the carboxylgroup, the present mat is safer for the animals even when they eat themat when compared with the case in which the fiber is supported by ametal as a deodorant agent.

(6) A small animal rearing cage for housing and rearing small animals,the small animal rearing cage comprising: a rearing box having a floorand a wall provided at a circumference of the floor; and a floor matformed with a sheet having a temperature holding property to a degreethat can keep the body temperature of the small animals, a flexibilityto a degree that can wrap the body of the small animals, and a size thatcovers at least the entire abdomen of the small animals.

(7) The small animal rearing cage according to (6), wherein the floormat is laid upon the floor of the rearing box in such a way that a pieceof sheet is folded each other to form folds.

According to the invention described in (6) and (7), a small animalrearing cage having similar effects as the invention described in (1)can be obtained.

Wherein the “small animals” reared in the small animal rearing cagerefers to animals reared as pets or for laboratory use that are fed andevacuates in the cage. As an example of small animals, there areRodentia including Muridae such as a rat and a hamster; Sciuridae suchas a squirrel, a flying squirrel, and a sugar glider; chinchilla and aguinea pig, and Leporidae such as a rabbit. The present invention ispreferably applied to the rearing of animals for a laboratory use suchas a rat and a mouse in Muridae, and particularly to the rearing of amouse having a size smaller than a rat.

It is preferable that the small animal rearing cage is provided withfeeders for food and water so that the animals can eat and evacuate.Upon rearing the small animals, a nest box is not necessary, however,may be provided in the cage as described above.

(8) The small animal rearing cage according to (6) or (7), wherein thefloor mat is a sheet larger in size than the floor area of the rearingbox.

According to the invention described in (8), the floor mat can coverentire surface of the floor in the small animal rearing cage so that itis easy for the animals to walk upon the mat and the surface of the matis prevented from being soiled with their excrement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an elevational view of a small animal rearing cage uponwhich a floor mat according to the present invention is laid.

FIG. 2 shows a small animal rearing cage in FIG. 1 housing and rearing amouse.

FIG. 3 shows an elevational view of a small animal rearing cage uponwhich a plurality of floor mats according to the present invention arelaid.

FIG. 4 shows a difference of the deodorization capacity between a floormat according to the present invention and other floor mats.

FIG. 5 shows a comparison of the deodorization capacity of the presentinvention between an unused floor mat and a mat after 2 months use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Details of the preferred embodiment of the present invention will bedescribed hereinafter with reference to the drawings in which likereference numerals designate identical or similar elements in each ofthe several views.

FIG. 1 is an elevational view of a small animal rearing cage 11 uponwhich a floor mat 60 according to the present invention is laid. Thesmall animal rearing cage 11 is provided with a rearing box 20. Therearing box 20 is made of transparent polycarbonate and comprises agenerally rectangle floor 30 and four walls 40 provided almost uprightat a circumference of the floor 30. Upon the floor 30 of the rearing box20, a sheet of floor mat 60 according to the present invention is foldedand laid to form folds 70. The upper part of the rearing box 20 iscovered with a removable cover 50 made of stainless wire. Upon a part ofthe cover 50, a recess 51 is formed and a bottle type water feeder 52 isinserted. Behind the water feeder 52, a pellet food (not shown) isprovided and the recess 51 is functioned as a food feeder in the presentembodiment.

The rearing box 20 according to the present embodiment has an outerdimension of Width 22 cm (W)×Depth 32 cm (D)×Height 13 cm (H). The sizeof the rearing box 20 is, however, not limited to the above butappropriately selected in a way that small animals can secure a space tosleep and move around freely in accordance with the size and number oftarget small animals. When rearing 1 to 6 mice, the outer dimensionrequired of the cage may be in a range of Width from 13 to 28 cm(W)×Depth from 20 to 45 cm (D)×Height from 11 to 18 cm (H).

The rearing box 20 is not limited to the one shown in FIG. 1 as long asthe floor mat 60 is laid thereupon and the box has a form and materialthat can house and raise small animals. As for a material of the rearingbox 20, plastics, such as polycarbonate, polypropylene, andacrylonitrilebutadienestyrene, metals, woods, or glasses can be used.The shape of the rearing box 20 is not limited to a general rectangularparallelepiped shown in FIG. 1 but may be a shape of a net or stripethat is wholly constituted with metallic wire.

It is preferable for the rearing box 20, particularly for the rearingbox 20 shown in FIG. 1 that the floor 30 is flat and the walls 40 aretransparent so that the box facilitates easy laying of the floor mat 60,easy observation of the small animals therein, and additionally theanimals can move around the box easily.

It is enough for the rearing box 20 to house small animals and the floormat 60 but it requires no flat walls 40 surrounding the floor mat 30.Instead, a groove or any member that prevents the small animals fromescaping from the rearing box 20 is equivalent to the wall 40.

The floor mat 60 according to the present invention will be describedhereinafter.

The floor mat 60 have a temperature holding property to a degree that itcan hold the body temperature of the small animals who are housed andreared in the rearing box 20, and also have a flexibility to a degreethat it can wrap the body of the small animals. The temperature holdingproperty mentioned here should be such a degree that an average skintemperature of 33 degrees C. can be kept when a sheet of the floor mat60 wraps the body of the small animals and keep them at an atmospherictemperature of 21 degrees C. with humidity of 50% and air flow 5 cm/secat a resting state. The appropriate value of do of the floor mat 60 isapproximately no less than 0.1 clo.

The required flexibility is such a degree that the floor mat 60 flexiblycurves along the shape of the body of the small animals when the mat iscovered thereupon. It should be noted that “provided with flexibility”herein means that the sheet type floor mat 60 has such flexibility thatthe floor mat 60 is not broken at a point where the mat is folded butkeep the seamless state of a sheet. It also has a softness that thefolded point is not automatically folded out by way of repulsion of thefloor mat 60. The flexibility specified herein is different from theconcept that the textile of the floor mat 60 is constituted with softmembers in a direction of thickness.

The floor mat 60 having the temperature holding property and flexibilitydescribed above includes a woven or non-woven fabric obtained fromnatural or synthetic fabric alone or in combination thereof, a softpaper such as a kitchen paper, a thin sponge fabric, or a surfacetreated vinyl sheet. In particular, fabrics are more preferred thanpapers because the fabric has more tearing resistance so that it can beprevented from being bitten by the small animals and torn into smallpieces, lumps or dusts.

The floor mat 60 according to the present invention has a size that cancover at least the entire abdomen of the small animals. In the smallanimal rearing cage 11 according to a first embodiment of the presentinvention shown in FIG. 1, the floor mat 60 is 8.5 times larger than thearea of the floor 30 and is laid crumpled and randomly thrown in therearing box 20. The floor mat 60 laid in such a way are folded randomlyand overlapped with one another to form folds 70 with various shapes andsizes. The floor mat 60 is folded and overlapped with each other to formthe folds 70 in which the recesses 71 or clearance 72 are formed with asize that can hide a part of the body of the animals. It is preferablethat the folds 70 have a size sufficient to hide a part or a half of thebody of the small animals. It is also preferable that a plurality offolds 70 is formed.

FIG. 2 shows a plurality of male and female mice 80 reared in the smallanimal rearing cage 11 shown in FIG. 1. The mouse 80 crawls in the folds70 or moves the floor mat 60 as appropriate to change the shapes of thefolds 70 freely to make the recesses 71 or clearances 72 for theirplaces to sleep (nest) or to evacuate.

Since the floor mat 60 has a flexibility to a degree that it can wrapthe body of the small animals and a temperature holding property to adegree that it can hold the body temperature of the small animals, thefloor mat 60 of the present invention functions as a bedding materialfor small animals that can wrap their body and keep their temperature inthe rearing box 20. Muridae such as mouse 80 evacuates at fixed placeacting on their instinct, so that the place for excrement is determinedas such. The excrements are trapped in the ridges and grooves formed onthe folds 70. The floor mat 60 as a whole is hardly removed by a mousemoving around the rearing box 20. The present invention, as beingdifferent from other mats that use small pieces such as chips for thefloor mat, prevents excrements from being spread over the floor 30 asthe mouse 80 moves around the cage along with small chips that areadhered with their excrements, thus deterioration of the rearingenvironment is avoided.

The formation of folds 70 helps mouse 80 to hide themselves in therecesses 71 or clearances 72 in order to avoid exposure to light orexternal air. The present invention provides mouse 80 a secured livingenvironment that releases the stress from the mouse, thereforeincreasing their chance of mating and improving fecundity. Conversely,the fecundity of the mouse 80 can be curbed by controlling theflexibility of the floor mat 60, or the number and the area to be laid.

According to the present invention, the mouse 80 can also use the folds70 to ensure a place for delivery and nursery of their baby animals andthus supplementary floor mat for breeding is not required. The sheettype floor mat 60 of the present invention hardly adheres to the bodysurface of the baby animals that have no hair. The baby animals can alsocrawl in the folds 70 to escape from being eaten by the mother animals,and thereby their survival rates are improved. It is preferable that thefloor mat 60 is provided with a tearing resistance because the mat ishardly torn off by biting of the mouse 80, and even when torn off, themat hardly generates small pieces or lumps that adhere easily to thebody of the small animals.

The floor mat may have at least a size that can cover the abdomen of thetarget animals, specifically, a size of approximately 10 cm in everydirection in the case where the target animal is a mouse. It ispreferable however that the floor mat has a size that is more than justenough to cover the small animals. It is preferable that the mat has asize of, for example, not less than 12 cm in every direction so that themat can cover the entire body including the head and abdomen of thesmall animals when they fold their limbs and crouch. It is preferablethat when the mat is a sheet having a size of 10 to 15 cm in everydirection, a plurality of floor mat is laid in such a way that at leastone or two of them are overlapped with one another to form folds.

In the present invention, however, it is preferable that the mat has asize that is 1.2 times, more preferably 2 to 15 times, furtherpreferably 3 to 10 times larger than the area of the floor 30 as shownin FIG. 1 and 2. A sheet of the floor mat 60 having such size can coverthe entire area of the floor 30 and form folds 70 to prevent the floor30 from being soiled and to make easy handling. A plurality of floormats 60 may be laid upon each other as shown in FIG. 3. As the mouse 80moves around, the floor mat 60 is moved to form folds 70. Upon laying aplurality of floor mats 60, the plurality of floor mats 60 may beoverlaid and a part or the entire circumference thereof may be sewn witha thread to unify as long as the formation of folds are secured. The useof a plurality of floor mats 60 can improve the deodorization capacity.

In addition to the temperature holding property and flexibility, it ispreferable that the floor mat 60 is provided with water absorptionproperty and deodorization property. In this case, the floor mat 60absorbs the urine of the small animals and also removes the offensiveodor substances such as ammonia and methyl mercaptan contained inexcrement and urine, allowing the use of the floor mat 60 for a longperiod of time.

As for the water absorption property, it is sufficient that the floormat 60 can hold liquid of no less than 10% by weight in relation to theweight of the mat; however, it is preferred for the floor mat 60 to holda liquid of 100 to 300% by weight in relation to the weight of the mat.And as for the deodorization property, it is preferable to removeoffensive odor substance of no less than 1 mg, more preferably 10 mg,and further preferably of no less than 15 mg.

The floor mat 60 provided with the temperature holding property,flexibility, and water absorption and deodorization properties includes:a deodorized fabric having such chemical fibers as acrylic and polyestercoated with deodorants, a deodorized fabric having such cellulose fibersas cotton, rayon, hemp, and wooden pulp supported by a metal, adeodorized fabric obtained from an introduction of carboxyl group, adeodorized fabric having chitin or chitosan as a source material, or adeodorized water absorptive sheet holding a deodorant such as activatedcarbon and an absorbent such as advanced aqueous resins.

Among above, the deodorized fabric that comprises natural fibers andthat is free from chemical substances has fewer detrimental effects onthe small animals even when they bite and ingest the fiber. Thedeodorized fabrics that comprise natural fibers include the deodorizedfabrics that have chitin or chitosan as a source material, or theimproved cellulose fabrics that are obtained from the introduction ofcarboxyl group into cellulose fibers. The improved cellulose fabric thathas cellulose fiber supported by polymethacrylate acid is preferable tothe chitin- or chitosan-contained deodorized fabric because they showhigher deodorization capacity. The deodorization capacity of theimproved cellulose fabric is such that 10 to 20 mg of the offensive odorsubstance per 1 g of improved cellulose can be removed, depending uponthe method.

For manufacturing the improved cellulose fabric, such cellulose fiber ascotton fiber, hemp fiber, rayon fiber, and wooden pulp are used as asource material, and chemical reaction process is required for anintroduction of the carboxyl group. In order to generate a reaction foran introduction of carboxyl group into cellulose fiber, for example,such methods are employed; a draft polymerization method in which thecarboxyl group-contained acrylic acid, methacrylic acid, orpolymethacrylic acid are draft polymerized into cellulose; atransformation of the primary hydroxyl group into carboxyl group throughcatalytic oxidation of cellulose according to the TEMPO methods (IsogaiAkira, “Magazine for The Society of Fiber Science and Technology” Vol.57, No. 6, P-163 (2001)), and a carboxymethylization method by usingmonochloroacetic acid. Upon introduction and reaction of carboxyl groupwith the source material, the carboxyl group-introduced cellulose fibercan be spine, or after the spinning of the cellulose fiber, the carboxylgroup can be introduced. Carboxyl may further be introduced into anon-woven fabric to provide a deodorization property. Uponpolymerization of methacrylic acid to a cellulose fiber, it ispreferable to process in such a way that methacrylic acid is polymerizedto have the improved cellulose fiber supported by polymethacrylic acid.

It is preferable that 40 to 140 millimole, more preferably 60 to 120millimole carboxyl group is contained per 100 g of dried fabric. Thecarboxyl group-contained within this range shows excellent waterabsorption and deodorization properties. The improved cellulose fabrichaving 40 to 140 millimole of carboxyl group per 100 g, for example, istheoretically provided with properties to remove and eliminate theoffensive odor that can absorb and decompose 1 to 2 g of ammonia. Thismeans that 1 g of improved cellulose fabric having 40 to 140 millimoleof carboxyl group per 100 g has a deodorization property that can remove10 to 20 mg of offensive odor substance, ammonia. Therefore when suchimproved cellulose fabrics are used as a floor mat, the mat can becontinuously used for as long as 7 to 10 days without being changed andstill keeps hygienically excellent rearing environment.

When too much carboxyl is contained in the improved cellulose fabric,the carboxyl introduction reaction requires longer time and increasesthe amount of use of reagent, and thus leads to higher manufacturingcosts. And it further deteriorates functions inherent in cellulose fibersuch as water absorption property. On the other hand, when too littlecarboxyl group is contained, satisfying deodorization property cannot beobtained. Or the contents of carboxyl group can be controlled by areaction time or an amount of use of the reagent. Or the contents of thecarboxyl group can also be controlled by a blending or mixture offibers, in which one has much carboxyl group and the other has nocarboxyl group.

As shown below, when carboxylic acid (COOH) is combined with ammonia(NH₃) that is an offensive odor substance, carboxylate ammonium (COONH₄)is generated in the improved cellulose that is introduced with carboxylto neutralize and remove the offensive odor substance.—COOH+NH₃→—COONH₄   [Formula 1]

The improved cellulose fabric has carboxyl group that neutralizes andabsorbs basic offensive odor substances, and is provided with waterabsorption and temperature holding properties and flexibility that areinherent in cellulose fiber, and further provided with tearingresistance property to protect the fabric from being bitten by themouse.

The improved cellulose fabric that is soiled after the use as a floormat can be washed, and by washing, the deodorization capacity can berecovered to a certain degree. Such improved cellulose fabric ismanufactured by blending an improved cotton thread with non-treatedcotton thread at a ratio of 1 to 1 by weight. In the improved cottonthread, polymethacrylic acid is introduced to the cellulose fiber bygraft polymerization of 10% by weight of methacrylic acid into cottonfiber, and supported. The improved cellulose fabric (having carboxylgroup contents of 70 millimole per 100 g of the floor mat) can be washedas much as 50 times to be used repeatedly. The improved cellulose fabricobtained from an oxidation of cotton fiber (having carboxyl groupcontents of 62 millimole per 100 g of the floor mat) according to theTEMPO method can also be washed as much as 50 times to be usedrepeatedly.

It is assumed that the deodorization capacity is recovered by a reactiondescribed below when the improved cellulose fabric is washed withneutral detergent and water or only with water.—COONH₄+H₂O→—COOH+NH₄OH   [Formula 2]

On the other hand, when the improved cellulose fabric is washed usingalkaline detergent, as shown in below formula, the sodium ion (—Na)dissolved in the contents of the detergent is easily combined withcarboxyl group that is substituted to ammonium ion (—NH4).—COONH₄+NaOH→—COONa+NH₄OH   [Formula 3]

From a view point of substitution of carboxyl, it is considered to bepreferable to use a neutral detergent to wash the improved cellulosefabric, however, an alkaline detergent may also be preferably used towash the improved cellulose fabric because alkaline detergents showhigher detergency than neutral detergents.

In order to obtain higher deodorization capacity, acidic substances suchas acetic acid, vinegar, or citrate may be added upon rinsing. It isassumed that when acetic acid (CH3COOH) is added upon rinsing, ammoniumion (NH4) of a carboxyl group is dropped off according to the followingchemical reaction and the ammonia deodorization capacity is recovered.It is considered that the deodorization capacity is recovered inproportion to the amount of acetic acid in relation to the fabricweight, not in proportion to the concentration of the acetic acid in thewashing water.—COONH₄+CH₃COOH→—COOH+CH₃COONH₄   [Formula 4]

[EXAMPLE]

Examples and Comparisons will be described hereinafter. A sheet of theimproved cellulose fabric was randomly crumpled to be rounded by handsand laid upon the rearing box of the small animals rearing cage(hereinafter referred to as a “cage”) as shown in FIG. 1. The rearingbox used was made of transparent polycarbonate resin having a size of 16cm in floor width, 26 cm in floor length, and 14 cm in height. Theimproved cellulose fabric was a form of a towel that blends a 33% ofnon-treated cotton thread with a 66% of cotton thread that havemethacrylic acid graft-polymered by 8% by weight to have polymethacrylicacid supported by cellulose fiber. The size of the improved cellulosefabric was 45 cm in width, 10 cm in length and 120 g in weight. Fivecages were prepared for example 1 and comparison 1 respectively andhoused in a rearing room that was ventilated about 15 times per hour. Atotal of six mice with one male and five females were reared in eachcage for two months. The top of the rearing cage was covered with astainless wire cover with a recess provided on a part thereof, and awater feeder as well as pellet food was inserted on the recess. Twosheets of the improved cellulose fabrics were prepared for each of thecage and the sheet was changed once a week. The sheet that had soiledwas washed with neutral detergent and used repeatedly. Floor mats werenot added even as delivery approached.

At comparison 1, instead of the use of the floor mat, the chip typepaper mat having a size of 5 mm in every direction was used butotherwise identical with example 1 and mice were similarly rearedthereon. Approximately 120 g of chip type floor mat was used in therearing box at a time and changed once a week. Tissue papers werefurther added upon delivery of mice.

Upon changing the floor mat, the situation with regard to the spreadingof excrement in the rearing box was observed. In the case of Example 1,the excrement of the mice remained accumulated almost at a specificplace on the improved cellulose fabric, and the improved cellulosefabric was clean as far as visually observed. On the contrary, in thecase of Comparison 1, excrements were scattered over the chip type floormat and mixed with the chips, and were spread all over the mat.

Concentration of ammonia in the cage was measured by using Kitagawa gasdetector (gas detector tube; 105SD & 105SC). In the case of Example 1,the value was 0.1 to 0.6 ppm on the third day after the laying (orchanging) of the floor mat and was 2.5 to 6.0 ppm just before thechanging of the mat on the seventh day. Whereas in the case ofComparison 1, the value was 0.1 to 0.6 ppm on the third day just as sameas Example 1, however the value was up to 12 to 30 ppm on the seventhday.

Semiconductor laser particle counter (KANOMAX, Model 3886 and TF 500)was further employed to measure the number of dust with a size of noless than 0.5 micrometers on the fifth day of rearing in the cage. Thevalue was 4.4 to 5.9×10⁵/m³ in Example 1, and 3.1 to 3.3×10⁷/m³ inComparison 1. In addition, no accumulation of dust was visually observedaround the rearing cage in Example 1 whereas several tens of dust wasscattered and accumulation of dust was visually observed around the cagein Comparison 1.

In Example 1, delivery and nursing of the baby mice was carried oututilizing folds. In particular, the baby mice crawled in the valley ofthe folds were raised there. As a result, in spite of the fact that inExample 1 no floor mats were added further for delivery and nursery, thegrowth curb of the baby mice were as identical as the result ofComparison 1 in which floor mats were added for the purpose of deliveryand nursery. Mother mice killed and ate their baby mice by 20 to 30percentage less in Example 1 than in Comparison 1. The number of matingof male mice was observed from 8 am to 5 pm every day from the onset ofthe rearing for duration of 1 to 2 weeks. The number observed was higherin Example 1 with 2 to 4 whereas 0 to 2 in Comparison 1.

As for Example 2, the improved cellulose fabric used in above Example 1;as for Comparison 2, the paper-made floor mat used in above Comparison1; and as for Comparison 3, a cotton fabric were prepared to observedeodorization property by way of the measurement of the concentration ofammonia. Three mat having 3.5 g in dry weight were placed respectivelyinto a tedlar bag having a size of 25 cm×40 cm (made by Sun Plastics).Initial ammonia concentration was set to 200 ppm and the container wassealed. The ammonia concentration was measured 1, 3, 5, 10 and 30minutes after the sealing to observe the deodorization property. Theamount of ammonia absorption was 21 mg per 1 g in the improved cellulosefabric in Example 1, and 3 mg per 1 g in the cotton fabric in Comparison3.

FIG. 4 illustrates a graph showing a test results of Example 2,Comparison 2 and Comparison 3 wherein the ordinate represents residualammonia concentration (unit: ppm) whereas the abscissa representselapsed time (unit: minute). The line P, A, B and C respectively shows achange of ammonia concentration in the tedlar bag in the containerwherein the line P represents Example 2 wherein the improved cellulosefabric was laid, the line A represents Comparison 2 wherein the papermat was laid, the line B represents Comparison 3 wherein a cotton fabricwas laid, and the line C represents a blank in which no specimen wereused.

As shown in FIG. 4, the residual ammonia concentration in the containerwas hardly detected in Example 2 after five minutes from the beginningof the experiment but on the other hand, Comparison 2 and 3 shownresidual ammonia concentration even 10 minutes after the beginning ofthe experiment.

As for Example 3 and Example 4, deodorization capacity was examined byobserving the condition of the improved cellulose fabric of Example 1with one fabric unused and the other fabric used for 2 months. Thespecimen weighed 120 g in dry weight was laid in the cage of Example 1.Ammonia solution of 50 ml with 1% concentration was poured in the cageand a change of ammonia concentration was observed. FIG. 5 illustratesthe results wherein the ordinate represents residual ammoniaconcentration (unit: ppm) whereas the abscissa represents elapsed time(unit: minute). The line P1 shows a change of residual ammoniaconcentration in the cage in which unused improved cellulose fabric waslaid as a specimen. The line P2 shows a change of residual ammoniaconcentration in the cage in which the improved cellulose fabric waslaid as a specimen and washed once a week for a period of two months. Asfor Comparison 4, (new) deodorized floor mat made of paper pulp was laidinstead of the improved cellulose fabric of Comparison 2. The change ofresidual ammonia concentration in the cage was shown with the line D.

As shown in FIG. 5, the change of residual ammonia concentration wasalmost similar between a new improved cellulose fabric and the improvedcellulose fabric that had been used for two months. On the other hand,the deodorized floor mat made of paper pulp shown a poor deodorizationcapacity compared with the improved cellulose fabric.

Similar tests as above were conducted between two fabrics and similartest results were obtained. The fabric used are: the improved cellulosefabric (having carboxyl group contents of 70 millimole per 100 g offloor mat) that was obtained from a blending of the improved fiberresulted from graft polymerization of 10% by weight of acrylic acid intoa cotton fiber, and non-treated cotton fiber at a ratio of 1 to 1 byweight; and the improved cellulose fabric (having carboxyl groupcontents of 62 millimole per 100 g of floor mat) that was obtained fromthe oxidation of a floor mat made of cotton according to the TEMPOmethod.

EFFECTS OF THE INVENTION

According to the present invention, a sheet type floor mat having atemperature holding property and flexibility is provided to be laid uponthe floor of the small animal rearing cage in such a way that the matforms folds to cover and hide the body of the animals, and thereforeprevents the animals from being exposed to the light and wind andreduces their stress. The sheet type floor mat prevents dust generation,traps excrement at the folds and prevents the excrement to be spreadover.

The sheet type floor mat when provided with water absorption anddeodorization properties can strongly remove the offensive odorsubstances such as ammonia that originally generates from excrement andurine of the small animals in a short period of time and therefore canmaintain excellent hygienic conditions in the small animal rearing cageand rearing room. Curving the generation of the offensive odor decreasesthe number of ventilation time for air conditioning, and so an effect isexpected of reducing the consumption of the electricity which is causedby exhaustion of heat.

When the improved cellulose fabric having polymethacrylic acid supportedby cellulose is used as a floor mat, in addition to the effectsdescribed above, the mat can recover the water absorption property and adeodorization property by washing and drying of the mat. The improvedcellulose fabric can thus be repeatedly used and reduces the totalamount of waste disposal.

1. A floor mat laid in a small animals rearing cage for housing andrearing small animals, said floor mat is a sheet comprising atemperature holding property to a degree that can keep the bodytemperature of said small animals, a flexibility to a degree that canwrap the body of said small animals, and a size that covers at least theentire abdomen of said small animals.
 2. The floor mat according toclaim 1, comprising a size for covering at least the abdomen and thehead of said small animals.
 3. The floor mat according to claim 1,further comprising a water absorption property and deodorizationproperty.
 4. The floor mat according to claim 1, further comprising atearing resistance.
 5. The floor mat according to claim 4, comprising animproved cellulose fabric wherein carboxyl group-introduced cellulose isformed in a shape of sheet.
 6. A small animal rearing cage for housingand rearing small animals, said small animal rearing cage comprising: arearing box having a floor and a wall provided at a circumference ofsaid floor; and a floor mat formed with a sheet having a temperatureholding property to a degree that can keep the body temperature of saidsmall animals, a flexibility to a degree that can wrap the body of saidsmall animals, and a size that covers at least the entire abdomen ofsaid small animals
 7. The small animal rearing cage according to claim6, wherein said floor mat is laid upon the floor of said rearing box insuch a way that a piece of sheet is folded each other to form folds. 8.The small animal rearing cage according to claim 6, wherein said floormat is a sheet larger in size than the floor area of said rearing box.9. The floor mat according to claim 2, further comprising a waterabsorption property and deodorization property.
 10. The floor mataccording to claim 3, further comprising a tearing resistance.
 11. Thesmall animal rearing cage according to claim 7, wherein said floor matis a sheet larger in size than the floor area of said rearing box. 12.The floor mat according to claim 9, further comprising a tearingresistance.